Methods, infrastructure equipment and communications device

ABSTRACT

A method of operating an infrastructure equipment in a wireless communications system to support first and second random access procedures is provided, wherein a number of subcarriers used for an uplink message of the second random access procedure is smaller than a number of subcarriers used for a corresponding uplink message of the first random access procedure. The method comprises transmitting, to at least one communications device, a scheduling message comprising an indication of a first set of radio resources comprising a plurality of subcarriers to be used for a random access procedure message for the first random access procedure, determining a second set of radio resources to be used for a random access procedure message for the second random access procedure, and monitoring for a random access procedure message from the at least one communications device on the second set of radio resources.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/043,666, filed Sep. 30, 2020, which is based on PCT filingPCT/EP2019/058076, filed Mar. 29, 2019, which claims priority to EP18166205.7, filed Apr. 6, 2018, the entire contents of each areincorporated herein by reference.

BACKGROUND Field of Disclosure

The present disclosure relates to methods and various telecommunicationsapparatus for the allocation of subcarriers for communications betweeninfrastructure equipment and communications devices.

Description of Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Recent generation mobile telecommunication systems, such as those basedon the 3GPP defined UMTS and Long Term Evolution (LTE) architectures,are able to support a wider range of services than simple voice andmessaging services offered by previous generations of mobiletelecommunication systems. For example, with the improved radiointerface and enhanced data rates provided by LTE systems, a user isable to enjoy high data rate applications such as mobile video streamingand mobile video conferencing that would previously only have beenavailable via a fixed line data connection. In addition to supportingthese kinds of more sophisticated services and devices, it is alsoproposed for newer generation mobile telecommunication systems tosupport less complex services and devices which make use of the reliableand wide ranging coverage of newer generation mobile telecommunicationsystems without necessarily needing to rely on the high data ratesavailable in such systems. The demand to deploy such networks istherefore strong and the coverage area of these networks, i.e.geographic locations where access to the networks is possible, may beexpected to increase ever more rapidly.

Future wireless communications networks will therefore be expected toroutinely and efficiently support communications with a wider range ofdevices associated with a wider range of data traffic profiles and typesthan current systems are optimised to support. For example it isexpected future wireless communications networks will be expected toefficiently support communications with devices including reducedcomplexity devices, machine type communication (MTC) devices, highresolution video displays, virtual reality headsets and so on. Some ofthese different types of devices may be deployed in very large numbers,for example low complexity devices for supporting the “The Internet ofThings”, and may typically be associated with the transmissions ofrelatively small amounts of data with relatively high latency tolerance.

In view of this there is expected to be a desire for future wirelesscommunications networks, for example those which may be referred to as5G or new radio (NR) system/new radio access technology (RAT) systems,as well as future iterations/releases of existing systems, toefficiently support connectivity for a wide range of devices associatedwith different applications and different characteristic data trafficprofiles.

One example area of current interest in this regard includes theso-called “Internet of Things” or IoT for short. The Third GenerationPartnership Project (3GPP) has proposed in Release 13 of the 3GPPspecifications to develop technologies for supporting narrowband(NB)-IoT and so-called enhanced MTC (eMTC) operation using a LTE/4Gwireless access interface and wireless infrastructure. More recentlythere have been proposals to build on these ideas in Release 14 of the3GPP specifications with so-called enhanced NB-IoT (eNB-IoT) and furtherenhanced MTC (feMTC), and in Release 15 of the 3GPP specifications withso-called further enhanced NB-IoT (feNB-IoT) and even further enhancedMTC (efeMTC). See, for example, [1], [2], [3], [4]. At least somedevices making use of these technologies are expected to be lowcomplexity and inexpensive devices requiring relatively infrequentcommunication of relatively low bandwidth data. It is further expectedsome of these types of device may be required to operate in areas ofrelatively poor coverage, for example, in a basement or other locationwith relatively high penetration loss (e.g. for smart meter typeapplications), or in remote locations (e.g. for remote monitoringapplications), and this has given rise to proposals for enhancingcoverage, for example using repeat transmissions.

The increasing use of different types of terminal devices associatedwith different traffic profiles and requirements for coverageenhancement gives rise to new challenges for efficiently handlingcommunications in wireless telecommunications systems that need to beaddressed.

SUMMARY OF THE DISCLOSURE

The present disclosure can help address or mitigate at least some of theissues discussed above as defined in the appended claims.

Embodiments of the present technique can provide a method of operatingan infrastructure equipment in a wireless communications system tosupport first and second random access procedures, wherein a number ofsubcarriers used for an uplink message of the second random accessprocedure is smaller than a number of subcarriers used for acorresponding uplink message of the first random access procedure. Themethod comprises transmitting, to at least one communications device, ascheduling message comprising an indication of a first set of radioresources comprising a plurality of subcarriers to be used for a randomaccess procedure message for the first random access procedure,determining a second set of radio resources to be used for a randomaccess procedure message for the second random access procedure, whereinthe second set of radio resources comprises one or more subcarrierswhich are indicated by one or more characteristics of the schedulingmessage, and monitoring for a random access procedure message from theat least one communications device on the second set of radio resources.

Respective aspects and features of the present disclosure are defined inthe appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, but are notrestrictive, of the present technology. The described embodiments,together with further advantages, will be best understood by referenceto the following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings wherein likereference numerals designate identical or corresponding parts throughoutthe several views, and wherein:

FIG. 1 schematically represents some aspects of a LTE-type wirelesstelecommunication system which may be configured to operate inaccordance with certain embodiments of the present disclosure;

FIG. 2 schematically represents some aspects of a new radio accesstechnology (RAT) wireless communications system which may be configuredto operate in accordance with certain embodiments of the presentdisclosure;

FIG. 3 schematically represents an example random access procedure foruse by different types of terminal device;

FIG. 4 shows an example of a physical uplink shared channel (PUSCH)transmission using a single physical resource block (PRB) pair;

FIG. 5 shows an example of a sub-PRB PUSCH transmission;

FIG. 6 shows an example of how resource elements (REs) may be mapped toa resource unit (RU) for a sub-PRB transmission formed of subcarriersfrom each of a plurality of subframes;

FIG. 7 shows an example of subcarrier hopping within an RU;

FIG. 8 schematically represents some aspects of a wirelesscommunications system in accordance with embodiments of the presenttechnique;

FIG. 9 shows an example of a scheduled PRB indicating a set ofsubcarriers in a predetermined PRB in accordance with embodiments of thepresent technique;

FIG. 10 shows an example of a sub-PRB capable UE being scheduledmultiple PRBs in accordance with embodiments of the present technique;

FIG. 11 shows an example of a PRB to subcarrier hopping mapping inaccordance with embodiments of the present technique;

FIG. 12 shows an example of a Cell ID to subcarrier set mapping inaccordance with embodiments of the present technique;

FIG. 13 shows an example of a Cell ID to subcarrier hopping patternmapping in accordance with embodiments of the present technique;

FIG. 14 shows an example of a medium access control (MAC) protocol dataunit (PDU) for MAC random access responses (RARs) in accordance withembodiments of the present technique:

FIG. 15 shows an example of a set of subcarriers used for four differentUEs with allocations of three subcarriers per subframe in accordancewith embodiments of the present technique;

FIG. 16 shows an example of subcarrier hopping with different startingpositions in accordance with embodiments of the present technique; and

FIG. 17 shows a flow diagram illustrating a process of communication ina communications system in accordance with embodiments of the presenttechnique.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Long Term Evolution (LTE) Wireless Communications System

FIG. 1 provides a schematic diagram illustrating some basicfunctionality of a mobile telecommunications network/system 6 operatinggenerally in accordance with LTE principles, but which may also supportother radio access technologies, and which may be adapted to implementembodiments of the disclosure as described herein. Various elements ofFIG. 1 and certain aspects of their respective modes of operation arewell-known and defined in the relevant standards administered by the3GPP® body, and also described in many books on the subject, forexample. Holma H. and Toskala A [5]. It will be appreciated thatoperational aspects of the telecommunications networks discussed hereinwhich are not specifically described (for example in relation tospecific communication protocols and physical channels for communicatingbetween different elements) may be implemented in accordance with anyknown techniques, for example according to the relevant standards andknown proposed modifications and additions to the relevant standards.

The network 6 includes a plurality of base stations 1 connected to acore network 2. Each base station provides a coverage area 3 (i.e. acell) within which data can be communicated to and from communicationsdevices 4.

Although each base station 1 is shown in FIG. 1 as a single entity, theskilled person will appreciate that some of the functions of the basestation may be carried out by disparate, inter-connected elements, suchas antennas, remote radio heads, amplifiers, etc. Collectively, one ormore base stations may form a radio access network.

Data is transmitted from base stations 1 to communications devices 4within their respective coverage areas 3 via a radio downlink. Data istransmitted from communications devices 4 to the base stations 1 via aradio uplink. The core network 2 routes data to and from thecommunications devices 4 via the respective base stations 1 and providesfunctions such as authentication, mobility management, charging and soon. Terminal devices may also be referred to as mobile stations, userequipment (UE), user terminal, mobile radio, communications device, andso forth.

Services provided by the core network 2 may include connectivity to theinternet or to external telephony services. The core network 2 mayfurther track the location of the communications devices 4 so that itcan efficiently contact (i.e. page) the communications devices 4 fortransmitting downlink data towards the communications devices 4.

Base stations, which are an example of network infrastructure equipment,may also be referred to as transceiver stations, nodeBs, e-nodeBs, eNB,g-nodeBs, gNB and so forth. In this regard different terminology isoften associated with different generations of wirelesstelecommunications systems for elements providing broadly comparablefunctionality. However, certain embodiments of the disclosure may beequally implemented in different generations of wirelesstelecommunications systems, and for simplicity certain terminology maybe used regardless of the underlying network architecture. That is tosay, the use of a specific term in relation to certain exampleimplementations is not intended to indicate these implementations arelimited to a certain generation of network that may be most associatedwith that particular terminology.

New Radio Access Technology (5G) Wireless Communications System

An example configuration of a wireless communications network which usessome of the terminology proposed for NR and 5G is shown in FIG. 2 . InFIG. 2 a plurality of transmission and reception points (TRPs) 10 areconnected to distributed control units (DUs) 41, 42 by a connectioninterface represented as a line 16. Each of the TRPs 10 is arranged totransmit and receive signals via a wireless access interface within aradio frequency bandwidth available to the wireless communicationsnetwork. Thus within a range for performing radio communications via thewireless access interface, each of the TRPs 10, forms a cell of thewireless communications network as represented by a line 12. As suchwireless communications devices 14 which are within a radiocommunications range provided by the cells 12 can transmit and receivesignals to and from the TRPs 10 via the wireless access interface. Eachof the distributed units 41, 42 are connected to a central unit (CU) 40(which may be referred to as a controlling node) via an interface 46.The central unit 40 is then connected to the a core network 20 which maycontain all other functions required to transmit data for communicatingto and from the wireless communications devices and the core network 20may be connected to other networks 30.

The elements of the wireless access network shown in FIG. 2 may operatein a similar way to corresponding elements of an LTE network asdescribed with regard to the example of FIG. 1 . It will be appreciatedthat operational aspects of the telecommunications network representedin FIG. 2 , and of other networks discussed herein in accordance withembodiments of the disclosure, which are not specifically described (forexample in relation to specific communication protocols and physicalchannels for communicating between different elements) may beimplemented in accordance with any known techniques, for exampleaccording to currently used approaches for implementing such operationalaspects of wireless telecommunications systems, e.g. in accordance withthe relevant standards.

The TRPs 10 of FIG. 2 may in part have a corresponding functionality toa base station or eNodeB of an LTE network. Similarly the communicationsdevices 14 may have a functionality corresponding to the UE devices 4known for operation with an LTE network. It will be appreciatedtherefore that operational aspects of a new RAT network (for example inrelation to specific communication protocols and physical channels forcommunicating between different elements) may be different to thoseknown from LTE or other known mobile telecommunications standards.However, it will also be appreciated that each of the core networkcomponent, base stations and communications devices of a new RAT networkwill be functionally similar to, respectively, the core networkcomponent, base stations and communications devices of an LTE wirelesscommunications network.

In terms of broad top-level functionality, the core network 20 of thenew RAT telecommunications system represented in FIG. 2 may be broadlyconsidered to correspond with the core network 2 represented in FIG. 1 ,and the respective central units 40 and their associated distributedunits/TRPs 10 may be broadly considered to provide functionalitycorresponding to the base stations 1 of FIG. 1 . The term networkinfrastructure equipment/access node may be used to encompass theseelements and more conventional base station type elements of wirelesstelecommunications systems. Depending on the application at hand theresponsibility for scheduling transmissions which are scheduled on theradio interface between the respective distributed units and thecommunications devices may lie with the controlling node/central unitand/or the distributed units/TRPs. A communications device 14 isrepresented in FIG. 2 within the coverage area of the firstcommunication cell 12. This communications device 14 may thus exchangesignalling with the first central unit 40 in the first communicationcell 12 via one of the distributed units 10 associated with the firstcommunication cell 12.

It will further be appreciated that FIG. 2 represents merely one exampleof a proposed architecture for a new RAT telecommunications system inwhich approaches in accordance with the principles described herein maybe adopted, and the functionality disclosed herein may also be appliedin respect of wireless telecommunications systems having differentarchitectures.

Thus certain embodiments of the disclosure as discussed herein may beimplemented in wireless telecommunication systems/networks according tovarious different architectures, such as the example architectures shownin FIGS. 1 and 2 . It will thus be appreciated the specific wirelesstelecommunications architecture in any given implementation is not ofprimary significance to the principles described herein. In this regard,certain embodiments of the disclosure may be described generally in thecontext of communications between network infrastructureequipment/access nodes and a communications device, wherein the specificnature of the network infrastructure equipment/access node and thecommunications device will depend on the network infrastructure for theimplementation at hand. For example, in some scenarios the networkinfrastructure equipment/access node may comprise a base station, suchas an LTE-type base station 1 as shown in FIG. 1 which is adapted toprovide functionality in accordance with the principles describedherein, and in other examples the network infrastructure equipment maycomprise a control unit/controlling node 40 and/or a TRP 10 of the kindshown in FIG. 2 which is adapted to provide functionality in accordancewith the principles described herein.

Thus certain embodiments of the disclosure as discussed herein may beimplemented in wireless telecommunication systems/networks according tovarious different architectures, such as the example architectures shownin FIG. 1 and FIG. 2 . It will be appreciated the specific wirelesstelecommunications architecture in any given implementation is not ofprimary significance to the principles described herein. In this regard,certain embodiments of the disclosure may be described generally in thecontext of communications between network infrastructureequipment/access nodes and a terminal device, wherein the specificnature of the network infrastructure equipment/access node and theterminal device will depend on the network infrastructure for theimplementation at hand. For example, in some scenarios the networkinfrastructure equipment/access node may comprise a base station, suchas an LTE-type base station 1 as shown in FIG. 1 which is adapted toprovide functionality in accordance with the principles describedherein, and in other examples the network infrastructure equipment maycomprise a control unit/controlling node and/or a TRP 10 in a new RATarchitecture of the kind discussed above in relation to FIG. 2 .

Random Access (RACH) Procedure

In wireless telecommunications networks, such as LTE type networks,there are different Radio Resource Control (RRC) modes for terminaldevices. For example, it is common to support an RRC idle mode(RRC_IDLE) and an RRC connected mode (RRC_CONNECTED). A terminal devicein the idle mode may move to connected mode, for example because itneeds to transmit uplink data or respond to a paging request, byundertaking a random access procedure. The random access procedureinvolves the terminal device transmitting a preamble on a physicalrandom access channel and so the procedure is commonly referred to as aRACH or PRACH procedure/process.

Thus a conventional way for a terminal device (UE) in RRC idle mode toexchange data with a network involves the terminal device firstperforming an RRC connection procedure (random access procedure) withthe network. The RRC connection procedure involves the UE initiallytransmitting a random access request message (which may be triggeredautonomously by the UE determining it has data to transmit to thenetwork or in response to the network instructing the UE to connect tothe network). This is followed by RRC control message exchange betweenthe network and UE. After establishing an RRC connection and exchangingthe relevant data, the UE may then perform RRC disconnection and moveback into idle mode for power saving. This conventional approach may forconvenience be referred to herein as a legacy approach.

The random access procedure can be relatively inefficient if the amountof data to be communicated with the network is relatively small, forexample in terms of signalling overhead and associated UE power usage.There have therefore been proposals for a UE to communicatehigher-layer/user plane data with the network during the RRC connectionprocedure itself. One approach for this is referred to as Early DataTransmission (EDT) and allows the UE to transmit and/or receive dataduring the Random Access process whilst in idle mode, therebycommunicating the relevant data without the need to complete theestablishment of an RRC connection, which can be particularly helpfulfor infrequent and short messages type of traffic.

FIG. 3 is a ladder diagram that schematically shows message exchangebetween a UE and an eNodeB in a typical random access procedure toestablish an RRC connection, in this example in an LTE-based network.The UE starts the process in step S31 by transmitting a random accessrequest on a physical random access channel (PRACH in an LTE context),i.e. a random access preamble (RACH preamble), to the eNodeB. In stepS32, when the eNodeB detects this preamble it will respond with a RandomAccess Response message (RAR), which is also known as Message 2. The RARis scheduled by downlink control information (DCI) carried on a physicaldownlink control channel, e.g. MPDCCH in an LTE implementation formachine type communication (MTC) traffic, in a predefined Common SearchSpace (CSS). The RAR itself is transmitted on a physical downlink sharedchannel (PDSCH) resource allocated via the DCI. The DCI is addressed toan RA-RNTI (random access radio network temporary identifier) which isderived from the time and frequency resources used to transmit thepreamble in step S31, and the RAR will indicate which preamble theeNodeB has detected and is responding to. It may be noted it is possiblethat multiple UEs may transmit a random access request using the samePRACH preamble and in the same time and frequency resources. The RAR ofstep S32 also contains an uplink grant for the preamble the network isresponding to so that the UE that transmitted the preamble may use thisuplink grant to transmit an RRC Connection Request message, also knownas Message 3 to the eNodeB, in step S33. Message 3 also contains anindication of an identifier, ID, for the UE (e.g. a C-RNTI (cell radionetwork temporary identifier) or S-TMSI (system architecture evolution(SAE) temporary mobile subscriber identity) or a 40-bit random numbergenerated by the UE. The eNodeB will respond to Message 3, in step S34,with Message 4 which carries an RRC Connection Setup message. For thecase where multiple UEs use the same preamble. Message 4 providescontention resolution functionality, for example using a terminal deviceidentifier, such as C-RNTI or S-TMSI, transmitted in Message 3 (when aUE receives a Message 4 that contains a portion of the Message 3containing the UE ID that it transmitted earlier, it knows that therewas no contention on the Message 3 that it had transmitted). The RRCconnection is complete when the UE transmits Message 5 in step S35containing an RRC Connection Setup Complete message.

A previously proposed approach for EDT in uplink is for additional datato be transmitted in association with the RRC connection requestmessage, in Message 3 (step S33 in FIG. 3 ). For the legacy approach torandom access, Message 3 carries only control messages and therefore hasa limited Transport Block Size (TBS). In order for Message 3 to carrymore useful amounts of data, the 3GPP group has agreed to allow for anincrease in the TBS for Message 3 to 1000 bits. However, it has alsobeen agreed that an eNodeB need not fulfil an EDT request by allocatingresources for a TBS for Message 3 up to 1000 bits, but the eNodeB caninstead schedule a smaller TBS as for a legacy Message 3, for examplehaving regard to overall resource availability. In this case the UE may,for example, need to follow the legacy approach of establishing an RRCconnection to communicate the data rather than using EDT.

In order for the eNodeB to identify whether a UE has EDT capability/isrequesting an allocation of radio resources for EDT in Message 3, it hasbeen proposed that a set of available PRACH preambles be partitionedsuch that a sub-group of PRACH preambles is used by a UE supporting EDTto indicate to the eNodeB its capability and to request EDT over Message3

Sub-PRB PUSCH

In the legacy eMTC (Rel-13 and Rel-14), the smallest frequency resourceunit that the physical uplink shared channel (PUSCH) can occupy is oneresource block (RB), or a physical resource block (PRB) pair, i.e. 12subcarriers×1 subframe as shown in FIG. 4 , where the subcarriers areindexed from 00 to 11. This is termed as PRB level transmission, eventhough PRB refers to 12 subcarriers×1 slot (where 1 subframe=2 slots)—hence the smallest frequency resource the PUSCH occupies is a PRB pair.

One of the objectives of Rel-15 efeMTC is to improve the spectralefficiency in the uplink, and the agreed method is to use sub-PRBtransmission for PUSCH. That is, in the frequency domain, the resourcesoccupied by a PUSCH transmission are less than a single PRB (i.e. fewerthan the 12 subcarriers as shown in FIG. 4 are used). The agreed numberof subcarriers for efeMTC sub-PRB PUSCH transmissions is any of 6subcarriers, 3 subcarriers and “2-of-3” subcarriers (where 3 subcarriersare allocated for the UE, but only 2 are actually used by the UE). Inother words, the eNodeB can choose to schedule to the UE either 6subcarriers, 3 subcarriers or “2-of-3” subcarriers. Those skilled in theart would appreciate that 2-of-3 subcarriers is essentially the same as2 subcarrier transmission, but due to non-technical issues, 3subcarriers are used by the eNodeB. The benefits of sub-PRB include:

-   -   Higher power spectral density is achieved on the PUSCH        transmission; that is, the UE transmission power is concentrated        on a fewer number of subcarriers; and    -   Improved capacity is achieved at the network since more UEs can        be multiplexed in the same frequency resources.

Since only a fraction of an RB (or PRB pair) is used for PUSCH, theresources (i.e. Resource Elements (REs)) available within 1 subframewould be reduced (e.g. by half in a 6 subcarrier transmission, a quarterin a 3 subcarrier transmission, etc.) and therefore there is a reductionin the Transport Block Size (TBS) that can be supported with ameaningful code rate. Recognising this, the concept of a Resource Unit(RU), which was introduced for Rel-13 NB-IoT, is also employed forsub-PRB eMTC. The RU is the granularity for sub-PRB PUSCH transmissions,where the reduced number of REs in the frequency domain is offset byincreasing the time duration of the granularity, such that the totalnumber of REs is the same as (or similar) to that in one PRB pair. Forexample, for a 3 subcarrier transmission occupying subcarriers {0, 1, 2}as shown in FIG. 5 , the RU would consist of 3 subcarriers×4 subframesthereby giving the number of REs equivalent to that of a PRB pair.

It has also been agreed that the symbols are mapped to the REs of an RUin a subframe by subframe basis, as shown in FIG. 6 . Here we use an RUof 3 subcarriers×4 subframes (ms), and here the modulated symbols arefirstly mapped onto subframe SF #00 starting with subcarrier SC #00,working up to SC #02. Mapping then proceeds to subframe SF #01 and theprocess is repeated until SF #03. This method of RE mapping has thebenefit of maintaining the eNodeB process of managing an uplinktransmission on a subframe (i.e. 1 ms) basis (i.e. the eNodeB processingfor the RU-based mapping can reuse the processing used for legacytransmissions).

For PRB level transmission, a Transport Block (TB) can occupy more thanone PRB. Similarly, for sub-PRB transmission, a TB can occupy more thanone RU, and the number of RUs is denoted as I_(RU). Hence, a singlerepetition of a TB would occupy a duration that equals the RU length intime (T_(RU)) multiplied by the number of RUs (I_(RU)), i.e. a durationof (T_(RU)×I_(RU)).

RACH Message 3 Using Sub-PRB Transmission

One issue that requires consideration is whether Message 3 of the RACHprocess supports sub-PRB transmission. It should be noted that prior tothe transmission of Message 3, the only uplink information that the UEcan relay to the eNodeB is the PRACH preamble. That is in order for theeNodeB to differentiate a sub-PRB capable UE from one that is notcapable of sub-PRB, the PRACH preamble needs to be partitioned such thata group of preambles are reserved for sub-PRB capable UEs. However, itwas already agreed in 3GPP that Early Data Transmission (EDT) overMessage 3 is indicated using PRACH preamble and hence further partitionof the PRACH preamble/resources also for sub-PRB would reduce the PRACHresources for legacy UEs. It should also be appreciated that the PRACHpreamble needs to be partitioned into 4 groups to indicate the supportof EDT & sub-PRB, EDT without sub-PRB, sub-PRB without EDT and legacy.

One proposal is for the eNodeB to transmit two RARs—one for the legacyUE, and another for the sub-PRB capable UE. The eNodeB would thenperform blind decoding on the uplink resources that it scheduled for apotential legacy UE and a potential sub-PRB UE. This proposal was arguedto waste resources; firstly for transmitting two RARs, and secondly forreserving two sets of PUSCH resources (for legacy and for sub-PRB UEs).

Another proposal in [6] is to use dual implicit scheduling. Here, theuplink grant in the RAR is maintained and only 1 RAR is transmitted asper the legacy procedure. The network would indicate support for sub-PRBPUSCH and, for a UE that is capable of sub-PRB PUSCH transmission, itwould interpret the Repetition and the Resource Allocation field in theuplink grant differently to how a legacy UE would interpret it. If theResource Allocation indicates only 1 PRB is scheduled and theRepetition >1, the sub-PRB capable UE would interpret this as a sub-PRBtransmission. The number of subcarriers used is dependent upon theindicated Repetition and is selected to be multiples of the RU length intime.

An example is shown in Table 1 below, which is reproduced from [6], forthe 3 bit Repetition field of the uplink grant for CE Mode B (UE thatused PRACH resource corresponding to Coverage Enhancement level 2 and3), where the max repetition is 128. Here the eNodeB schedules only 1PRB and the UE would then read the indicated repetition to determine thenumber of subcarriers used. For example if the repetition is 8, thatmeans the UE (i.e. sub-PRB-capable UE) would transmit using 3subcarriers with a repetition of 2 (the legacy UE would transmit using12 subcarriers with a repetition of 8). It should be appreciated thatthe total transmission time, which is calculated as the repetition(R)×RU length in time (T_(RU))×Number of RU (I_(RU)) equals to thelength of the original indicated repetition transmission length. This isbeneficial for eNodeB scheduling since the same time resource isreserved whether the UE is sub-PRB capable or a legacy UE.

TABLE 1 Dual implicit scheduling interpretation for sub-PRB capable UESub-PRB Interpretation Indicated Repetitions, Repetition Number ofsubcarriers R T_(RU) I_(RU) R × T_(RU) × I_(RU) 1 12 subcarriers (1 PRB)1 N/A N/A l ms 2  6 subcarriers 1 2 1 2 ms 4  3 subcarriers 1 4 1 4 ms 8 3 subcarriers 2 4 1 8 ms 16  3 subcarriers 4 4 1 16 ms  32  3subcarriers 4 4 2 32 ms  64  3 subcarriers 4 4 4 64 ms  128  3subcarriers 8 4 4 128 ms 

Another aspect of dual implicit scheduling is that the transmission ofthe subframe within an RU performs frequency hopping (or subcarrierhopping) such that each subframe within an RU occupies differentsubcarriers. This is explained with an example shown in FIG. 7 . Here anRU of 3 subcarriers×4 subframes is allocated and instead of occupyingthe same set of subcarriers, the UE transmits using different sets ofsubcarriers in different subframes. In this example, in the subframe SF#00 the UE uses subcarriers {00, 01, 02}, in SF #01 subcarriers {03, 04,05} are used, in SF #02 subcarriers {06, 07, 08} are used and in SF #03subcarriers {09, 10, 11} are used. The eNodeB would blind decode for asub-PRB type transmission and a legacy transmission, for example bytaking into account which subcarriers and subframes contain PUSCH andwhich don't.

One problem with the dual implicit scheduling method is that there is nomechanism proposed for the eNodeB to decide on which 3 or 6 subcarriersin a subframe the UE should use. Embodiments of the present disclosureprovide solutions to this problem.

Subcarrier Allocation for RACH Message 3 Transmission in eMTC

Certain embodiments of the disclosure propose approaches in which asingle scheduling message transmitted by an infrastructure equipment(eNodeB) as part of a random access procedure may be interpreteddifferently by different types of communications device (UE). Forexample, the scheduling message may indicate a first set of radioresources comprising a plurality of subcarriers to be used by a legacyUE for a random access procedure message for the first random accessprocedure. However, a sub-PRB capable UE may be configured to interpretthe scheduling message as allocating a second set of radio resources tobe used by the sub-PRB capable UE for a random access procedure messagefor the second random access procedure, wherein the second set of radioresources comprises one or more subcarriers—where this number ofsubcarriers is smaller than the number of the plurality of subcarriersused by the legacy UE for the random access procedure message for thefirst random access procedure. Here, while the plurality of subcarriersmay number 12 per subframe, the one or more of the plurality ofsubcarriers which form the second set of radio resources may number, forexample, 3 or 6 per subframe. The specific 3 or 6 (for example)subcarriers of the subframe used for the second set of resources areimplicitly indicated by one or more characteristics of the schedulingmessage. This allows the eNodeB to use a single scheduling message toallocate different sets of radio resources for different UEs havingdifferent capabilities. The eNodeB is then able to monitor the secondset of resources for an RRC connection request (RACH procedure message3) from sub-PRB capable UEs. Optionally, the eNodeB can monitor both thefirst set of resources and the second set of resources for RRCconnection requests, such that it is able to receive these from bothsub-PRB capable UEs and legacy UEs.

FIG. 8 schematically shows a wireless communications system 80 accordingto an embodiment of the present disclosure. The wireless communicationssystem 80 in this example is based broadly around an LTE-typearchitecture. As such many aspects of the operation of the wirelesscommunications system/network 80 are known and understood and are notdescribed here in detail in the interest of brevity. Operational aspectsof the wireless communications system 80 which are not specificallydescribed herein may be implemented in accordance with any knowntechniques, for example according to the current LTE standards or NRstandards.

The wireless communications system 80 comprises a core network part(evolved packet core) 82 coupled to a radio network part. The radionetwork part comprises a base station (eNodeB) 84 coupled to a pluralityof communications devices. In this example, two communications devicesare shown, namely a first communications device 86 and a secondcommunications device 88. It will of course be appreciated that inpractice the radio network part may comprise a plurality of eNodeBsserving a larger number of communications devices across variouscommunication cells. However, only a single eNodeB and twocommunications devices are shown in FIG. 8 in the interests ofsimplicity.

As with a conventional mobile radio network, the communications devices86, 88 are arranged to communicate data to and from the eNodeB(transceiver station) 84. The eNodeB is in turn communicativelyconnected to a serving gateway, S-GW, (not shown) in the core networkpart which is arranged to perform routing and management of mobilecommunications services to the communications devices in the wirelesscommunications system 80 via the eNodeB 84. In order to maintainmobility management and connectivity, the core network part 82 alsoincludes a mobility management entity (not shown) which manages theenhanced packet service (EPS) connections with the communicationsdevices 86, 88 operating in the communications system based onsubscriber information stored in a home subscriber server (HSS). Othernetwork components in the core network (also not shown for simplicity)include a policy charging and resource function (PCRF) and a packet datanetwork gateway (PDN-GW) which provides a connection from the corenetwork part 82 to an external packet data network, for example theInternet. As noted above, the operation of the various elements of thecommunications system 80 shown in FIG. 8 may be broadly conventionalapart from where modified to provide functionality in accordance withembodiments of the present disclosure as discussed herein.

In this example, it is assumed the first communications device 86 is aconventional smartphone-type communications device communicating withthe eNodeB 84 in a conventional manner (i.e. the first communicationsdevice is a legacy communications device that does not support sub-PRBtransmission). It will be appreciated the first communications deviceneed not be a smartphone-type communications device and could equally beanother type of legacy communications device, including a device thathas the capability to support sub-PRB transmission, but is currently notdoing so. The conventional/legacy communications device 86 comprisestransceiver circuitry 86 a (which may also be referred to as atransceiver 1 transceiver unit) for transmission and reception ofwireless signals and processor circuitry 86 b (which may also bereferred to as a processor/processor unit) configured to control thedevice 86. The processor circuitry 86 b may comprise varioussub-units/sub-circuits for providing functionality as explained furtherherein. These sub-units may be implemented as discrete hardware elementsor as appropriately configured functions of the processor circuitry.Thus the processor circuitry 86 b may comprise circuitry which issuitably configured/programmed to provide the desired functionalityusing conventional programming/configuration techniques for equipment inwireless communications systems. The transceiver circuitry 86 a and theprocessor circuitry 86 b are schematically shown in FIG. 8 as separateelements for ease of representation. However, it will be appreciatedthat the functionality of these circuitry elements can be provided invarious different ways, for example using one or more suitablyprogrammed programmable computer(s), or one or more suitably configuredapplication-specific integrated circuit(s)/circuitry/chip(s)/chipset(s).As will be appreciated the legacy (non-sub-PRB capable) communicationsdevice 86 will in general comprise various other elements associatedwith its operating functionality.

In this example, it is assumed the second communications device 88 is amachine-type communication (MTC or eMTC or efeMTC) communications device88 adapted to support sub-PRB transmission (i.e. the secondcommunications device may be referred to as a sub-PRB capablecommunications device/UE). In this regard, the second communicationsdevice 88 may be a reduced capability communications device, for examplea communications device able to operate on a restricted bandwidth ascompared to conventional communications devices (i.e. what might bereferred to as a narrowband device). However, it will be appreciatedthis represents merely one specific implementation of approaches inaccordance with embodiments of the disclosure, and in other cases, thesame principles may be applied in respect of communications devices thatsupport sub-PRB transmission but which are not reduced capabilitycommunications devices, but may, for example, comprise smartphonecommunications devices, or indeed any other form of communicationsdevice, that may be operating in a wireless communications system. Itwill be appreciated that a sub-PRB capable communications device mayalso function as a non-sub-PRB capable/legacy communications device,e.g. when it does not want to use sub-PRB transmission.

The sub-PRB capable communications device 88 comprises transceivercircuitry 88 a (which may also be referred to as atransceiver/transceiver unit) for transmission and reception of wirelesssignals and processor circuitry 88 b (which may also be referred to as aprocessor/processor unit) configured to control the communicationsdevice 88. The processor circuitry 88 b may comprise varioussub-units/sub-circuits for providing desired functionality as explainedfurther herein. These sub-units may be implemented as discrete hardwareelements or as appropriately configured functions of the processorcircuitry. Thus the processor circuitry 88 b may comprise circuitrywhich is suitably configured/programmed to provide the desiredfunctionality described herein using conventionalprogramming/configuration techniques for equipment in wirelesscommunications systems. The transceiver circuitry 88 a and the processorcircuitry 88 b are schematically shown in FIG. 8 as separate elementsfor ease of representation. However, it will be appreciated that thefunctionality of these circuitry elements can be provided in variousdifferent ways, for example using one or more suitably programmedprogrammable computer(s), or one or more suitably configuredapplication-specific integrated circuit(s)/circuitry/chip(s)/chipset(s).It will be appreciated the communications device 88 will in generalcomprise various other elements associated with its operatingfunctionality, for example a power source, user interface, and so forth,but these are not shown in FIG. 8 in the interests of simplicity.

The eNodeB 84 comprises transceiver circuitry 84 a (which may also bereferred to as a transceiver/transceiver unit) for transmission andreception of wireless signals and processor circuitry 84 b (which mayalso be referred to as a processor/processor unit) configured to controlthe eNodeB 84 to operate in accordance with embodiments of the presentdisclosure as described herein. The processor circuitry 84 b maycomprise various sub-units/sub-circuits for providing desiredfunctionality as explained further herein. These sub-units may beimplemented as discrete hardware elements or as appropriately configuredfunctions of the processor circuitry. Thus the processor circuitry 84 bmay comprise circuitry which is suitably configured/programmed toprovide the desired functionality described herein using conventionalprogramming/configuration techniques for equipment in wirelesscommunications systems. The transceiver circuitry 84 a and the processorcircuitry 84 b are schematically shown in FIG. 8 as separate elementsfor ease of representation. However, it will be appreciated that thefunctionality of these circuitry elements can be provided in variousdifferent ways, for example using one or more suitably programmedprogrammable computer(s), or one or more suitably configuredapplication-specific integrated circuit(s)/circuitry/chip(s)/chipset(s).It will be appreciated the eNodeB 84 will in general comprise variousother elements associated with its operating functionality.

As described above, embodiments of the present technique implicitlyindicate the set of the subcarriers within the scheduled PRB whensub-PRB transmission for Message 3 of the RACH procedure is scheduled.Embodiments of the present disclosure can be divided into two broadcategories:

-   -   The eNodeB is unaware whether the UE transmitting the PRACH is        sub-PRB capable or is a legacy UE; and    -   The eNodeB is aware that a UE transmitting a PRACH is sub-PRB        capable or is a legacy UE. This can be achieved by        partitioning/reserving some PRACH resources such as preambles        for use only by sub-PRB capable UEs. It should be appreciated        that Early Data Transmission (EDT) over Message 3 uses the PRACH        partitioning method to inform the eNodeB of the UE's capability        and intention to use EDT, as described above. It has also been        previously proposed that an EDT capable UE will also mandatorily        support sub-PRB transmission.

In an example arrangement, the sub-PRB transmission is only applicableto a set of predetermined narrowbands in frequency. That is, if any ofthese predetermined narrowbands (or sub-bands) are scheduled then the UEfollows one of the sub-PRB transmission arrangements as described below.In other words, in this example arrangement, the infrastructureequipment only monitors for the random access procedure message from theat least one communications device on the second set of radio resourcesif the infrastructure equipment has scheduled the at least onecommunications device to transmit signals to the infrastructureequipment using radio resources within at least one of a set ofpredetermined frequency sub-bands. The set of predetermined narrowbandscan be signalled in the system information blocks (SIBs) or can bespecified in the specifications, for example as a function of cell IDand system bandwidth. Hence, only UEs allocated into these predeterminedsets of narrowbands are allowed to use sub-PRB transmission for Message3, even if they would otherwise be capable. It should be noted such anarrangement is applicable to both the sub-PRB-unaware and sub-PRB-awareexample RACH processes as described below.

Sub-PRB Unaware RACH

Some embodiments of the present technique can provide examplearrangements for cases where the eNodeB does not know whether a receivedPRACH (preamble) is from a sub-PRB capable UE or a legacy UE. In otherwords, in these embodiments, the infrastructure equipment is unaware ofwhether or not the at least one communications device is capable oftransmitting the random access procedure message using the second set ofradio resources.

In an example arrangement, the scheduled (single) PRB would implicitlyindicate the set of subcarriers to be used. In other words, in thisexample arrangement, the characteristics of the scheduling message whichindicates the subcarriers forming the second set of radio resourcescomprise a mapping between the subcarriers forming the first set ofradio resources and the subcarriers forming the second set of radioresources (for example, the mapping links a position/location of thesubcarriers of the first set of resources within the narrowband withthose subcarriers used for the second set of resources, e.g. within aPRB). The indicated set of subcarriers to be used may be in apredetermined PRB (i.e. the second set of radio resources is selectedfrom a predetermined set of resources). An example is shown in FIG. 9 ,where the said predetermined PRB is PRB #05 and a one to one mapping ofscheduled PRB to set of subcarriers for the 3 subcarriers case is shownsuch that if a UE e.g. UE1 is scheduled to use PRB #00, it woulddirectly map to subcarriers {SC #00, SC #01, SC #02} in thepredetermined PRB #05. Similarly PRB #01 maps to subcarriers {SC #03, SC#04, SC #05} of PRB #05. PRB #02 maps to subcarriers {SC #06, SC #07. SC#08} of PRB #05 and PRB #03 maps to subcarriers {SC #09, SC #10, SC #11}of PRB #05. A legacy UE receiving the UL grant would directly use thescheduled PRB. For example if UE1 is a legacy UE and UE2 is sub-PRBcapable, an eNodeB (who is not aware whether these UEs are sub-PRBcapable or legacy) can schedule UE1 to use PRB #00 and UE2 to use PRB#01. Here UE1 would use the entire (all subcarriers) in PR #00 whilstUE2 will use subcarriers {SC #03, SC #04, SC #05} in PRB #05. The eNodeBcan then perform blind decodes on PRB #00 and PRB #01 for potentialMessage 3 from legacy UEs and subcarriers {SC #00, SC #01, SC #02} andsubcarriers {SC #03, SC #04, SC #05} for potential Message 3 fromsub-PRB capable UEs. It should be appreciated that a similar mapping canbe made for the 6 subcarrier case, e.g. PRB #00 maps to subcarriers {SC#00, SC #01. SC #02, SC #03, SC #04, SC #05} and PRB #01 maps tosubcarriers {SC #06, SC #07, SC #08, SC #09, SC #10, SC #11}.

It should be appreciated that an implementation where the pre-determinedPRB is the scheduled PRB is also feasible. That is for example in FIG. 9, if UE2 is allocated to PRB #01 then it would use subcarrier {SC #03,SC #04, SC #05} of PRB #01. Similarly UE3 being scheduled to use PRB #02would use subcarrier {SC #06, SC #07, SC #08} of the scheduled PRB #02.

It should also be noted that the UE only needs to perform the PRB tosubcarrier mapping if it is scheduled to perform sub-PRB transmission,i.e. when it is scheduled with a single PRB and repetition >1 asdescribed in Table I. Otherwise, the sub-PRB capable UE will use thescheduled PRBs directly. For example, in FIG. 10 , two sub-PRB capableUEs, UE1 and UE2 are being scheduled by the eNodeB. UE1 is scheduled touse PRB #01 with 4× repetitions and UE2 is being scheduled to use PRB#03 and PRB #04 (multiple PRBs). Since UE1 is sub-PRB capable, thisresource allocation would implicitly tell UE1 to use 3 subcarriers forits Message 3 transmission and to map them to subcarriers {SC #03, SC#04, SC #05} in PRB #05 (where PRB #05 is the predetermined PRB). UE2 isbeing allocated multiple PRBs which implicitly tells it NOT to usesub-PRB transmission for its Message 3 and would therefore directly usethe allocated PRBs (PRB #03, PRB #04) for its transmission. It should beappreciated that the examples in FIG. 9 and FIG. 10 are only one way ofmapping PRB to subcarriers and other mapping is possible.

In one example arrangement the PRB to subcarrier mapping is broadcast inthe SIBs (e.g. whether PRB #00 maps to {SC #00, SC #01, SC #02} or it ismapped to some other set of subcarriers such as {SC #03, SC #04, SC #05}etc.).

In another example arrangement the predetermined PRB is broadcast in theSIBs (e.g. whether the predetermined PRB is PRB #05 in FIG. 6 , PRB #04or same as the scheduled PRB, etc).

In another example arrangement the predetermined PRB is specified in thespecifications. A possible implementation is that this predetermined PRBis a function of the narrowband used, e.g. if Narrowband #00 is usedthen the predetermined PRB is PRB #00, Narrowband #01 means PRB #01 isthe predetermined PRB, etc. A wrap around can be implemented e.g. ifNarrowband #06 is used then the predetermined PRB is PRB #00, ifNarrowband #07 is used then predetermined PRB is PRB #01.

In another example arrangement the PRB to subcarrier mapping isspecified in the specifications. This can be a function of where thepredetermined PRB is and/or a function of the scheduled narrowband.

In another example arrangement the PRB to subcarrier mapping alsoindicates the subcarrier hopping (frequency hopping) pattern. That isinstead of mapping to only one set of subcarriers, the PRB wouldimplicitly indicate the set of subcarriers used throughout thetransmission of the transport block. In other words, in this examplearrangement, the characteristics of the scheduling message whichindicates the subcarriers forming the second set of radio resourcescomprise a hopping pattern defining a mapping between the subcarriersforming the first set of radio resources and the subcarriers forming thesecond set of radio resources, wherein the subcarriers forming thesecond set of radio resources comprises a plurality of distinct sets ofsubcarriers. An example of PRB to subcarrier hopping pattern is shown inFIG. 11 , where like in FIG. 9 , four of the (six) PRBs are mapped tospecific subcarriers in the predetermined PRB (PRB #05). However, unlikeFIG. 9 , the set of subcarriers used by the UEs are different indifferent subframes as shown in FIG. 11 . It should be appreciated thatalthough here the subcarriers are hopped at every subframe, this examplearrangement can be applied for subcarrier hopping with a longer durationin each subcarrier, e.g. the subcarrier is hopped every 4 subframes.

In another example arrangement, the set of subcarrier used by the UE isa function of the Cell ID of the serving cell. This allows neighbouringcells to use different sets of subcarriers for sub-PRB transmission ofMessage 3 thereby randomising the interference. A UE is allocated a PRBand either uses that PRB for a legacy transmission (12 subcarriers wide)or for a sub-PRB transmission, but when the UE transmits a sub-PRBPUSCH, the subcarriers used for that sub-PRB PUSCH are a function of thecell ID. For example, in FIG. 12 , 3 subcarriers are allocated to a UEin two different cells, with Cell ID #1 and Cell ID #2. In Cell ID #1the UE would use subcarrier set {SC #00, SC #01, SC #02} whenever 3subcarriers are allocated and in Cell ID #2 the UE would use subcarrierset {SC #06, SC #07, SC #09} whenever 3 subcarriers are allocated. Inother words, in this example arrangement, the characteristics of thescheduling message which indicates the subcarriers forming the secondset of radio resources comprise a mapping between a cell identifier of acoverage area provided by the infrastructure equipment and thesubcarriers forming the second set of radio resources.

If subcarrier hopping is used, then each Cell ID would indicate adifferent subcarrier hopping. In other words, in this examplearrangement, the characteristics of the scheduling message whichindicates the subcarriers forming the second set of radio resourcescomprise a hopping pattern defining a mapping between the cellidentifier of the coverage area provided by the infrastructure equipmentand the subcarriers forming the second set of radio resources, whereinthe subcarriers forming the second set of radio resources comprises aplurality of distinct sets of subcarriers. An example is shown in FIG.13 where the subcarrier occupied by the UE is different in differentsubframes and the subcarrier hopping pattern for a UE in Cell ID #1 andanother in Cell ID #2 follows a different hopping sequence where thehopping sequence is a function of the serving cell ID.

In the arrangements described above relating to Cell ID, the Cell ID tosubcarrier or to subcarrier hopping mapping can be specified in thespecifications.

Sub-PRB Aware RACH

Some embodiments of the present technique can provide examplearrangements for cases where the eNodeB is aware of whether or not aPRACH (preamble) is received from a UE that is capable of sub-PRBtransmission for Message 3. In other words, in these embodiments, theinfrastructure equipment is aware of whether or not the at least onecommunications device is capable of transmitting the random accessprocedure message using the second set of radio resources.

In an example arrangement, the set of subcarriers used by a UE isdependent upon the location of the UE's RAR within the MAC PDU (i.e. theMAC PDU that is transmitted in Msg2). This enables the eNodeB tomultiplex multiple sub-PRB Message 3 transmission into a PRB therebyimproving capacity. In other words, in this example arrangement, thecharacteristics of the scheduling message which indicates thesubcarriers forming the second set of radio resources comprise a mappingbetween a location within the scheduling message of a portion thescheduling message which is relevant to the at least one communicationsdevice and the subcarriers forming the second set of radio resources. Inthe existing system, multiple RARs are multiplexed in a single MAC PDUas shown in FIG. 14 (which can be found in Section 6.1.5 of [7]), wherethe MAC header indicates the PRACH resources that the eNodeB isresponding to and the position of the MAC header would match theposition of the MAC RAR for that UE. Hence, in this example arrangement,the position of the MAC RAR would implicitly tell the UE the set ofsubcarriers the UE should use. An example is shown in FIG. 15 , wherethe RAR responds to 4 different UEs (UE1, UE2, UE3, U4) and the 1^(st)MAC RAR position (e.g. MAC RAR1 in FIG. 14 ) implicitly indicates to thethat UE to use subcarriers {SC #00, SC #01, SC #02}, the 2^(nd) MAC RARposition indicates subcarriers {SC #03, SC #04, SC #05}, the 3^(rd) MACRAR position indicates subcarriers {SC #06, SC #07, SC #08} and the4^(th) MAC RAR position indicates subcarriers {SC #09, SC #10, SC #11}.Hence, the eNodeB can easily multiplex these 4 UEs by assigning UE1 toMAC RAR position 1, UE2 to position 2. UE3 to position 3 and UE4 toposition 4. A wraparound can be used such that the 5^(th) MAC RARposition indicates subcarriers {SC #00, SC #01, SC #02} again (note theeNodeB can schedule a different PRB for the 5^(th) UE). One way ofexpressing the subcarrier SC(n) within a PRB used for the n^(th)subcarrier within an allocated N_(SC) subcarriers (e.g. N_(SC)=3 or 6)as a function of the P_(RAR) MAC RAR position the UE in the MAC PDU is:

${{SC}(n)} = {{{MOD}( {n,N_{SC}} )} + ( {{{MOD}( {P_{RAR},\frac{12}{N_{SC}}} )} \times N_{SC}} )}$

Where, n={0, 1, . . . , N_(SC)−1}, SC={0, 1, 2, . . . , 11}, P_(RAR)={0,1, 2, . . . }. Such a function can be specified in the specifications.It should be appreciated other functions of the MAC RAR position can beused, e.g. one can easily find another function that places the 1^(st)UE in the MAC RAR in subcarrier {SC #09, SC #10, SC #11} instead of {SC#00, SC #01, SC #02}.

For the case where frequency or subcarrier hopping is used, the MAC RARposition P_(RAR) would indicate the starting position and the subcarrierhopping can be a simple offset of N_(SC). An example is shown in FIG. 16where the set of subcarriers in the 1^(st) subframe (SF #00) followsthose in FIG. 15 and in subsequent subframes, the subcarrier is offsetby 3 subcarriers. In other words, the characteristics of the schedulingmessage which indicates the subcarriers forming the second set of radioresources comprise a hopping pattern defining a mapping between thelocation within the scheduling message of the portion the schedulingmessage which is relevant to the at least one communications device andthe subcarriers forming the second set of radio resources, wherein thesubcarriers forming the second set of radio resources comprises aplurality of distinct sets of subcarriers.

In another example arrangement, the set of subcarriers or the startingset of subcarriers (for subcarrier hopping) is implicitly indicated bythe PRACH resource used. The PRACH resource consists of frequency, timeand preamble and a combination of these would indicate the set ofsubcarriers used. In other words, in this example arrangement, thescheduling message is transmitted to the at least one communicationsdevice in response to receiving a physical random access channel, PRACH,signal comprising a preamble signature from the at least onecommunications device, and the characteristics of the scheduling messagewhich indicates the subcarriers forming the second set of radioresources comprise a mapping between one or more of frequency resourcesused for the PRACH signal, time resources used for the transmission ofthe PRACH signal, and the preamble signature of the PRACH signal, andthe subcarriers forming the second set of radio resources. Whensubcarrier hopping is used in this example arrangement, thecharacteristics of the scheduling message which indicates thesubcarriers forming the second set of radio resources comprise a hoppingpattern defining a mapping between one or more of the frequencyresources used for the PRACH signal, the time resources used for thetransmission of the PRACH signal, and the preamble signature of thePRACH signal, and the subcarriers forming the second set of radioresources, wherein the subcarriers forming the second set of radioresources comprises a plurality of distinct sets of subcarriers.

In another example arrangement, the set of subcarriers or the startingset of subcarriers is determined from the UE RA-RNTI. In other words, inthis example arrangement, the characteristics of the scheduling messagewhich indicates the subcarriers forming the second set of radioresources comprise a mapping between a random access radio networktemporary identifier, RA-RNTI, of the at least one communications deviceand the subcarriers forming the second set of radio resources. Whensubcarrier hopping is used in this example arrangement, thecharacteristics of the scheduling message which indicates thesubcarriers forming the second set of radio resources comprise a hoppingpattern defining a mapping between the RA-RNTI of the at least onecommunications device and the subcarriers forming the second set ofradio resources, wherein the subcarriers forming the second set of radioresources comprises a plurality of distinct sets of subcarriers. Itshould be noted that the RA-RNTI is a function of the PRACH resource andthis example arrangement is basically a special case of the previousexample arrangement of the set of subcarriers or the starting set ofsubcarriers (for subcarrier hopping) being implicitly indicated by thePRACH resource used. An example function can be, where RNTI=RA-RNTI ofthe UE:

${{SC}(n)} = {{{MOD}( {n,N_{SC}} )} + (  {MOD}({{RNTI},{\frac{12}{N_{SC}} \times N_{SC}}} ) }$

It should be appreciated that the eNodeB has less scheduling controlwhen using the PRACH resources or RA-RNTI to determine the subcarrierlocations since the eNB is unable to control the PRACH resources used bythe UE.

Flow Chart Representation

FIG. 17 shows a flow diagram illustrating a process of communications ina communications system in accordance with embodiments of the presenttechnique. The process shown by FIG. 17 is a method of operating aninfrastructure equipment in a wireless communications system to supportfirst and second random access procedures, wherein a number ofsubcarriers used for an uplink message of the second random accessprocedure is smaller than a number of subcarriers used for acorresponding uplink message of the first random access procedure.

The method begins in step S171. The method comprises, in step S172,transmitting, to at least one communications device, a schedulingmessage comprising an indication of a first set of radio resourcescomprising a plurality of subcarriers to be used for a random accessprocedure message for the first random access procedure. The processproceeds to step S173, which comprises determining a second set of radioresources to be used for a random access procedure message for thesecond random access procedure, wherein the second set of radioresources comprises one or more subcarriers which are indicated by oneor more characteristics of the scheduling message. The process thenproceeds to step S174, which comprises monitoring for a random accessprocedure message from the at least one communications device on thesecond set of radio resources. The process ends in step S175.

Those skilled in the art would appreciate that the method shown by FIG.17 may be adapted in accordance with embodiments of the presenttechnique. For example, other intermediate steps may be included in themethod, or the steps may be performed in any logical order.

Those skilled in the art would also appreciate that such infrastructureequipment and/or wireless communications networks as herein defined maybe further defined in accordance with the various arrangements andembodiments discussed in the preceding paragraphs. It would be furtherappreciated by those skilled in the art that such infrastructureequipment and wireless communications networks as herein defined anddescribed may form part of communications systems other than thosedefined by the present invention.

It will be appreciated that while the present disclosure has in somerespects focused on implementations in an LTE-based and/or 5G networkfor the sake of providing specific examples, the same principles can beapplied to other wireless telecommunications systems. Thus, even thoughthe terminology used herein is generally the same or similar to that ofthe LTE and 5G standards, the teachings are not limited to the presentversions of LTE and 5G and could apply equally to any appropriatearrangement not based on LTE or 5G and/or compliant with any otherfuture version of an LTE, 5G or other standard.

It may be noted various example approaches discussed herein may rely oninformation which is predetermined/predefined in the sense of beingknown by both the base station and the terminal device. It will beappreciated such predetermined/predefined information may in general beestablished, for example, by definition in an operating standard for thewireless telecommunication system, or in previously exchanged signallingbetween the base station and terminal devices, for example in systeminformation signalling, or in association with radio resource controlsetup signalling, or in information stored on a SIM card. That is tosay, the specific manner in which the relevant predefined information isestablished and shared between the various elements of the wirelesstelecommunications system is not of primary significance to theprinciples of operation described herein. It may further be notedvarious example approaches discussed herein rely on information which isexchanged/communicated between various elements of the wirelesstelecommunications system and it will be appreciated such communicationsmay in general be made in accordance with conventional techniques, forexample in terms of specific signalling protocols and the type ofcommunication channel used, unless the context demands otherwise. Thatis to say, the specific manner in which the relevant information isexchanged between the various elements of the wirelesstelecommunications system is not of primary significance to theprinciples of operation described herein.

It will be appreciated that the principles described herein are notapplicable only to certain types of terminal device, but can be appliedmore generally in respect of any types of terminal device, for examplethe approaches are not limited to machine type communication devices/IoTdevices or other narrowband terminal devices, but can be applied moregenerally, for example in respect of any type terminal device operatingwith a wireless link to the communication network.

The following numbered paragraphs provide further example aspects andfeatures of the present technique:

Paragraph 1. A method of operating an infrastructure equipment in awireless communications system to support first and second random accessprocedures, wherein a number of subcarriers used for an uplink messageof the second random access procedure is smaller than a number ofsubcarriers used for a corresponding uplink message of the first randomaccess procedure, and wherein the method comprises:

-   -   transmitting, to at least one communications device, a        scheduling message comprising an indication of a first set of        radio resources comprising a plurality of subcarriers to be used        for a random access procedure message for the first random        access procedure;    -   determining a second set of radio resources to be used for a        random access procedure message for the second random access        procedure, wherein the second set of radio resources comprises        one or more subcarriers which are indicated by one or more        characteristics of the scheduling message; and    -   monitoring for a random access procedure message from the at        least one communications device on the second set of radio        resources.        Paragraph 2. A method according to Paragraph 1, wherein the        infrastructure equipment monitors for the random access        procedure message on both the first set of radio resources and        the second set of radio resources.        Paragraph 3. A method according to Paragraph 1 or Paragraph 2,        wherein the scheduling message is a random access response        message, transmitted to the at least one communications device        in response to receiving a physical random access channel,        PRACH, signal comprising a preamble signature from the at least        one communications device.        Paragraph 4. A method according to any preceding Paragraph,        wherein the infrastructure equipment monitors for the random        access procedure message from the at least one communications        device on the second set of radio resources if the        infrastructure equipment has scheduled the at least one        communications device to transmit signals to the infrastructure        equipment using radio resources within at least one of a set of        predetermined frequency sub-bands.        Paragraph 5. A method according to any preceding Paragraph,        wherein the infrastructure equipment is unaware of whether or        not the at least one communications device is capable of        transmitting the random access procedure message using the        second set of radio resources.        Paragraph 6. A method according to Paragraph 5, wherein the        characteristics of the scheduling message which indicates the        subcarriers forming the second set of radio resources comprise a        mapping between the subcarriers forming the first set of radio        resources and the subcarriers forming the second set of radio        resources.        Paragraph 7. A method according to Paragraph 6, wherein the        second set of radio resources is selected from a predetermined        set of radio resources.        Paragraph 8. A method according to Paragraph 5 or Paragraph 6,        wherein the characteristics of the scheduling message which        indicates the subcarriers forming the second set of radio        resources comprise a hopping pattern defining a mapping between        the subcarriers forming the first set of radio resources and the        subcarriers forming the second set of radio resources, wherein        the subcarriers forming the second set of radio resources        comprises a plurality of distinct sets of subcarriers.        Paragraph 9. A method according to any of Paragraphs 5 to 8,        wherein the characteristics of the scheduling message which        indicates the subcarriers forming the second set of radio        resources comprise a mapping between a cell identifier of a        coverage area provided by the infrastructure equipment and the        subcarriers forming the second set of radio resources.        Paragraph 10. A method according to Paragraph 9, wherein the        characteristics of the scheduling message which indicates the        subcarriers forming the second set of radio resources comprise a        hopping pattern defining a mapping between the cell identifier        of the coverage area provided by the infrastructure equipment        and the subcarriers forming the second set of radio resources,        wherein the subcarriers forming the second set of radio        resources comprises a plurality of distinct sets of subcarriers.        Paragraph 11. A method according to any preceding Paragraph,        wherein the infrastructure equipment is aware of whether or not        the at least one communications device is capable of        transmitting the random access procedure message using the        second set of radio resources.        Paragraph 12. A method according to Paragraph 11, wherein the        characteristics of the scheduling message which indicates the        subcarriers forming the second set of radio resources comprise a        mapping between a location within the scheduling message of a        portion the scheduling message which is relevant to the at least        one communications device and the subcarriers forming the second        set of radio resources.        Paragraph 13. A method according to Paragraph 11 or Paragraph        12, wherein the characteristics of the scheduling message which        indicates the subcarriers forming the second set of radio        resources comprise a hopping pattern defining a mapping between        the location within the scheduling message of the portion the        scheduling message which is relevant to the at least one        communications device and the subcarriers forming the second set        of radio resources, wherein the subcarriers forming the second        set of radio resources comprises a plurality of distinct sets of        subcarriers.        Paragraph 14. A method according to any of Paragraphs 11 to 13,        wherein the scheduling message is transmitted to the at least        one communications device in response to receiving a physical        random access channel, PRACH, signal comprising a preamble        signature from the at least one communications device, and the        characteristics of the scheduling message which indicates the        subcarriers forming the second set of radio resources comprise a        mapping between one or more of frequency resources used for the        PRACH signal, time resources used for the transmission of the        PRACH signal, and the preamble signature of the PRACH signal,        and the subcarriers forming the second set of radio resources.        Paragraph 15. A method according to Paragraph 14, wherein the        characteristics of the scheduling message which indicates the        subcarriers forming the second set of radio resources comprise a        hopping pattern defining a mapping between one or more of the        frequency resources used for the PRACH signal, the time        resources used for the transmission of the PRACH signal, and the        preamble signature of the PRACH signal, and the subcarriers        forming the second set of radio resources, wherein the        subcarriers forming the second set of radio resources comprises        a plurality of distinct sets of subcarriers.        Paragraph 16. A method according to any of Paragraphs 11 to 15,        wherein the characteristics of the scheduling message which        indicates the subcarriers forming the second set of radio        resources comprise a mapping between a random access radio        network temporary identifier, RA-RNTI, of the at least one        communications device and the subcarriers forming the second set        of radio resources.        Paragraph 17. A method according to Paragraph 16, wherein the        characteristics of the scheduling message which indicates the        subcarriers forming the second set of radio resources comprise a        hopping pattern defining a mapping between the RA-RNTI of the at        least one communications device and the subcarriers forming the        second set of radio resources, wherein the subcarriers forming        the second set of radio resources comprises a plurality of        distinct sets of subcarriers.        Paragraph 18. An infrastructure equipment for use in a wireless        communications system to support first and second random access        procedures, wherein a number of subcarriers used for an uplink        message of the second random access procedure is smaller than a        number of subcarriers used for a corresponding uplink message of        the first random access procedure, and wherein the        infrastructure equipment comprises controller circuitry and        transceiver circuitry configured in combination:    -   to transmit, to at least one communications device, a scheduling        message comprising an indication of a first set of radio        resources comprising a plurality of subcarriers to be used for a        random access procedure message for the first random access        procedure;    -   to determine a second set of radio resources to be used for a        random access procedure message for the second random access        procedure, wherein the second set of radio resources comprises        one or more subcarriers which are indicated by one or more        characteristics of the scheduling message; and    -   to monitor for a random access procedure message from the at        least one communications device on the second set of radio        resources.        Paragraph 19. Circuitry for an infrastructure equipment for use        in a wireless communications system to support first and second        random access procedures, wherein a number of subcarriers used        for an uplink message of the second random access procedure is        smaller than a number of subcarriers used for a corresponding        uplink message of the first random access procedure, and wherein        the infrastructure equipment comprises controller circuitry and        transceiver circuitry configured in combination:    -   to transmit, to at least one communications device, a scheduling        message comprising an indication of a first set of radio        resources comprising a plurality of subcarriers to be used for a        random access procedure message for the first random access        procedure;    -   to determine a second set of radio resources to be used for a        random access procedure message for the second random access        procedure, wherein the second set of radio resources comprises        one or more subcarriers which are indicated by one or more        characteristics of the scheduling message; and    -   to monitor for a random access procedure message from the at        least one communications device on the second set of radio        resources.        Paragraph 20. A method of operating a communications device in a        wireless communications system that supports first and second        random access procedures, wherein a number of subcarriers used        for an uplink message of the second random access procedure is        smaller than a number of subcarriers used for a corresponding        uplink message of the first random access procedure, and wherein        the method comprises:    -   receiving, from an infrastructure equipment of the wireless        communications system, a scheduling message comprising an        indication of a first set of radio resources comprising a        plurality of subcarriers to be used for a random access        procedure message for the first random access procedure;    -   determining a second set of radio resources to be used for a        random access procedure message for the second random access        procedure, wherein the second set of radio resources comprises        one or more subcarriers which are indicated by one or more        characteristics of the scheduling message; and    -   transmitting a random access procedure message to the        infrastructure equipment using the second set of radio        resources.        Paragraph 21. A communications device for use in a wireless        communications system that supports first and second random        access procedures, wherein a number of subcarriers used for an        uplink message of the second random access procedure is smaller        than a number of subcarriers used for a corresponding uplink        message of the first random access procedure, and wherein the        communications device comprises controller circuitry and        transceiver circuitry configured in combination:    -   to receive, from an infrastructure equipment of the wireless        communications system, a scheduling message comprising an        indication of a first set of radio resources comprising a        plurality of subcarriers to be used for a random access        procedure message for the first random access procedure;    -   to determine a second set of radio resources to be used for a        random access procedure message for the second random access        procedure, wherein the second set of radio resources comprises        one or more subcarriers which are indicated by one or more        characteristics of the scheduling message; and    -   to transmit a random access procedure message to the        infrastructure equipment using the second set of radio        resources.        Paragraph 22. Circuitry for a communications device for use in a        wireless communications system that supports first and second        random access procedures, wherein a number of subcarriers used        for an uplink message of the second random access procedure is        smaller than a number of subcarriers used for a corresponding        uplink message of the first random access procedure, and wherein        the communications device comprises controller circuitry and        transceiver circuitry configured in combination:    -   to receive, from an infrastructure equipment of the wireless        communications system, a scheduling message comprising an        indication of a first set of radio resources comprising a        plurality of subcarriers to be used for a random access        procedure message for the first random access procedure;    -   to determine a second set of radio resources to be used for a        random access procedure message for the second random access        procedure, wherein the second set of radio resources comprises        one or more subcarriers which are indicated by one or more        characteristics of the scheduling message; and    -   to transmit a random access procedure message to the        infrastructure equipment using the second set of radio        resources.

It will be appreciated that the above description for clarity hasdescribed embodiments with reference to different functional units,circuitry and/or processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits, circuitry and/or processors may be used without detracting fromthe embodiments.

Described embodiments may be implemented in any suitable form includinghardware, software, firmware or any combination of these. Describedembodiments may optionally be implemented at least partly as computersoftware running on one or more data processors and/or digital signalprocessors. The elements and components of any embodiment may bephysically, functionally and logically implemented in any suitable way.Indeed the functionality may be implemented in a single unit, in aplurality of units or as part of other functional units. As such, thedisclosed embodiments may be implemented in a single unit or may bephysically and functionally distributed between different units,circuitry and/or processors.

Although the present disclosure has been described in connection withsome embodiments, it is not intended to be limited to the specific formset forth herein. Additionally, although a feature may appear to bedescribed in connection with particular embodiments, one skilled in theart would recognise that various features of the described embodimentsmay be combined in any manner suitable to implement the technique.

REFERENCES

-   [1] RP-161464. “Revised WID for Further Enhanced MTC for LTE,”    Ericsson, 3GPP TSG RAN Meeting #73, New Orleans, USA, Sep. 19-22,    2016.-   [2] RP-161901, “Revised work item proposal: Enhancements of NB-IoT”,    Huawei, HiSilicon, 3GPP TSG RAN Meeting #73, New Orleans, USA, Sep.    19-22, 2016.-   [3] RP-170732, “New WID on Even further enhanced MTC for LTE,”    Ericsson, Qualcomm, 3GPP TSG RAN Meeting #75. Dubrovnik. Croatia,    Mar. 6-9, 2017.-   [4] RP-170852, “New WID on Further NB-IoT enhancements,” Huawei,    HiSilicon, Neul, 3GPP TSG RAN Meeting #75, Dubrovnik, Croatia, Mar.    6-9, 2017.-   [5] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based    radio access”, John Wiley and Sons, 2009.-   [6] R1-1717762, “Sub-PRB Design Analysis,” Sierra Wireless, RAN1    #90bis.-   [7] TS36.321. “Medium Access Control (MAC) protocol specification    (Release 14)” v14.0.0.

What is claimed is:
 1. Circuitry for an infrastructure equipment for usein a wireless communications system to support first and second randomaccess procedures, wherein a first number of subcarriers used for anuplink message of the second random access procedure is different than asecond number of subcarriers used for a corresponding uplink message ofthe first random access procedure, and wherein the circuitry isconfigured to: transmit, to at least one communications device, ascheduling message comprising an indication of a first set of radioresources to be used for a random access procedure message for the firstrandom access procedure, wherein one or more characteristics of thescheduling message indicate a second set of radio resources to be usedfor a random access procedure message for the second random accessprocedure; and monitor for a random access procedure message from the atleast one communications device on the second set of radio resources,wherein the scheduling message is a random access response message,transmitted to the at least one communications device in response toreceiving a physical random access channel (PRACH) signal comprising apreamble signature from the at least one communications device.
 2. Thecircuitry of claim 1, wherein the circuitry is configured to monitorsfor the random access procedure message on both the first set of radioresources and the second set of radio resources.
 3. The circuitry ofclaim 1, wherein the circuitry is configured to monitor for the randomaccess procedure message from the at least one communications device onthe second set of radio resources if the infrastructure equipment hasscheduled the at least one communications device to transmit signals tothe infrastructure equipment using radio resources within at least oneof a set of predetermined frequency sub-bands.
 4. The circuitry of claim1, wherein the infrastructure equipment is unaware of whether or not theat least one communications device is capable of transmitting the randomaccess procedure message using the second set of radio resources.
 5. Thecircuitry of claim 4, wherein the characteristics of the schedulingmessage which indicates subcarriers forming the second set of radioresources comprise a mapping between subcarriers forming the first setof radio resources and subcarriers forming the second set of radioresources.
 6. The circuitry of claim 5, wherein the second set of radioresources is selected from a predetermined set of radio resources. 7.The circuitry of claim 5, wherein the characteristics of the schedulingmessage which indicates subcarriers firming the second set of radioresources comprise a hopping pattern defining a mapping betweensubcarriers forming the first set of radio resources and the subcarriers forming the second set of radio resources.
 8. The circuitry ofclaim 7, wherein the subcarriers forming the second set of radioresources comprises a plurality of distinct sets of subcarriers.
 9. Thecircuitry of claim 4, wherein the characteristics of the schedulingmessage which indicates subcarriers forming the second set of radioresources comprise a mapping between a cell identifier of a coveragearea provided by the infrastructure equipment and subcarriers formingthe second set of radio resources.
 10. The circuitry of claim 9, whereinthe characteristics of the scheduling message which indicates thesubcarriers forming the second set of radio resources comprise a hoppingpattern defining a mapping between the cell identifier of the coveragearea provided by the infrastructure equipment and the subcarriersforming the second set of radio resources, and the subcarriers formingthe second set of radio resources comprises a plurality of distinct setsof subcarriers.
 11. The circuitry of claim 1, wherein the infrastructureequipment is aware of whether or not the at least one communicationsdevice is capable of transmitting the random access procedure messageusing the second set of radio resources.
 12. The circuitry of claim 11,wherein the characteristics of the scheduling message which indicatessubcarriers forming the second set of radio resources comprise a mappingbetween a location within the scheduling message of a portion thescheduling message which is relevant to the at least one communicationsdevice and the subcarriers forming the second set of radio resources.13. The circuitry of claim 12, wherein the characteristics of thescheduling message which indicates the subcarriers forming the secondset of radio resources comprise a hopping pattern defining a mappingbetween the location within the scheduling message of the portion thescheduling message which is relevant to the at least one communicationsdevice and the subcarriers forming the second set of radio resources,wherein the subcarriers forming the second set of radio resourcescomprises a plurality of distinct sets of subcarriers.
 14. The circuitryof claim 11, wherein the scheduling message is transmitted to the atleast one communications device in response to receiving a physicalrandom access channel (PRACH) signal comprising a preamble signaturefrom the at least one communications device, and the characteristics ofthe scheduling message which indicates subcarriers forming the secondset of radio resources comprise a mapping between one or more offrequency resources used for the PRACH signal, time resources used forthe transmission of the PRACH signal, and the preamble signature of thePRACH signal, and the subcarriers forming the second set of radioresources.
 15. The circuitry of claim 14, wherein the characteristics ofthe scheduling message which indicates the subcarriers forming thesecond set of radio resources comprise a hopping pattern defining themapping between one or more of the frequency resources used for thePRACH signal, the time resources used for the transmission of the PRACHsignal, and the preamble signature of the PRACH signal, and thesubcarriers forming the second set of radio resources, and thesubcarriers forming the second set of radio resources comprises aplurality of distinct sets of subcarriers.
 16. The circuitry of claim11, wherein the characteristics of the scheduling message whichindicates subcarriers forming the second set of radio resources comprisea mapping between a random access radio network temporary identifier(RA-RNTI) of the at least one communications device and the subcarriersforming the second set of radio resources.
 17. The circuitry of claim16, wherein the characteristics of the scheduling message whichindicates the subcarriers forming the second set of radio resourcescomprise a hopping pattern defining the mapping between the RA-RNTI ofthe at least one communications device and the subcarriers forming thesecond set of radio resources, and the subcarriers forming the secondset of radio resources comprises a plurality of distinct sets ofsubcarriers.
 18. A method of operating a communications device in awireless communications system that supports first and second randomaccess procedures, wherein a number of subcarriers used for an uplinkmessage of the second random access procedure is different than a numberof subcarriers used for a corresponding uplink message of the firstrandom access procedure, and wherein the method comprises: receiving,from an infrastructure equipment of the wireless communications system,a scheduling message comprising an indication of a first set of radioresources to be used for a random access procedure message for the firstrandom access procedure; determining a second set of radio resources tobe used for a random access procedure message for the second randomaccess procedure, wherein the second set of radio resources areindicated by one or more characteristics of the scheduling message; andtransmitting a random access procedure message to the infrastructureequipment using the second set of radio resources, wherein thescheduling message is a random access response message received by thecommunications device in response to transmitting a physical randomaccess channel (PRACH) signal comprising a preamble signature from thecommunications device.
 19. Circuitry for a communications device for usein a wireless communications system that supports first and secondrandom access procedures, wherein a number of subcarriers used for anuplink message of the second random access procedure is different than aumber of subcarriers used for a corresponding uplink message of thefirst random access procedure, and wherein the circuitry is configuredto: receive; from an infrastructure equipment of the wirelesscommunications system, a scheduling message comprising an indication ofa first set of radio resources to be used for a random access proceduremessage for the first random access procedure; determine a second set ofradio resources to be used for a random access procedure message for thesecond random access procedure, wherein the second set of radioresources are indicated by one or more characteristics of the schedulingmessage; and transmit a random access procedure message to theinfrastructure equipment using the second set of radio resources,wherein the scheduling message is a random access response messagereceived by the communications device in response to transmitting aphysical random access channel (PRACH) signal comprising a preamblesignature from the communications device.